THE OLDEST AIR-BREATHERS 263 



Parrsboro', found on one of the slabs a very distinct series of 

 footprints, each with four toes, and a trace of the fifth. Dr. 

 Harding's specimen is now in the museum of King's College, 

 Windsor. Its impressions are more distinct, but not very 

 different otherwise from those above described, as found at 

 Horton Bluff. The rocks at that place are probably of nearly 

 the same age with those of Parrsboro'. I afterward examined 

 the place from which this slab had been quarried, and satisfied 

 myself that the beds are Carboniferous, and probably Lower 

 Carboniferous. They were ripple-marked and sun-cracked, 

 and I thought I could detect some footprints, though more 

 obscure than those in Dr. Harding's slab. Similar footprints 

 are also stated to have been found by Dr. Gesner, at Parrs- 

 boro'. All of these were from the lowest beds of the Carboni- 

 ferous system. 



I have since observed several instances of such impressions 

 at the Joggins, at Horton, and near Windsor, showing that 

 they are by no means rare, and that reptilian animals existed 

 in no inconsiderable numbers throughout the coal field of 

 Nova Scotia, and from the beginning to the end of the Carbo- 

 niferous period. Most of these, when well preserved, show five 

 toes both on the anterior and posterior limb. On comparing 

 these earlier Carboniferous footprints with one another, it will 

 be observed that they are of similar general character, and 

 may have been made by one kind of animal, which must have 

 had* the fore and hind feet nearly of equal size, and a digiti- 

 grade mode of walking. Footprints of similar form are found 

 in the coal formation, as well as others of much larger size. 

 The latter are of two kinds. One of these shows short hind 

 feet of digitigrade character and a long stride, in this resem- 

 bling the smaller footprints of the Lower Carboniferous, which 

 are remarkable for the length of limb which they indicate by 

 the distance between the footprints. The other kind shows 

 long hind feet, as if the whole heel were brought down to the 



